package com.yupi.yupicturebackend.service.impl;

import cn.hutool.core.util.ObjUtil;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.yupi.yupicturebackend.exception.BusinessException;
import com.yupi.yupicturebackend.exception.ErrorCode;
import com.yupi.yupicturebackend.exception.ThrowUtils;
import com.yupi.yupicturebackend.mapper.SpaceMapper;
import com.yupi.yupicturebackend.model.dto.space.analyze.*;
import com.yupi.yupicturebackend.model.entity.Picture;
import com.yupi.yupicturebackend.model.entity.Space;
import com.yupi.yupicturebackend.model.entity.User;
import com.yupi.yupicturebackend.model.vo.space.analyze.*;
import com.yupi.yupicturebackend.service.PictureService;
import com.yupi.yupicturebackend.service.SpaceAnalyzeService;
import com.yupi.yupicturebackend.service.SpaceService;
import com.yupi.yupicturebackend.service.UserService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

@Service
public class SpaceAnalyzeServiceImpl extends ServiceImpl<SpaceMapper, Space> implements SpaceAnalyzeService {

    @Resource
    private UserService userService;

    @Resource
    private SpaceService spaceService;

    @Resource
    private PictureService pictureService;
    private void checkSpaceAnalyzeAuth(SpaceAnalyzeRequest spaceAnalyzeRequest, User loginUser){
        boolean queryPublic = spaceAnalyzeRequest.isQueryPublic();
        boolean queryAll = spaceAnalyzeRequest.isQueryAll();
        // 个人空间和全空间分析都需要有管理员权限
        if(queryPublic||queryAll){
            ThrowUtils.throwIf(!userService.isAdmin(loginUser), ErrorCode.NO_AUTH_ERROR);
        }else{
            //分析特定空间，仅本人或者管理员可以访问
            Long spaceId = spaceAnalyzeRequest.getSpaceId();
            ThrowUtils.throwIf(spaceId==null,ErrorCode.PARAMS_ERROR);
            Space space = this.getById(spaceId);
            ThrowUtils.throwIf(space == null, ErrorCode.NOT_FOUND_ERROR, "空间不存在");
            spaceService.checkSpaceAuth(loginUser,space);
        }
    }

    @Override
    public SpaceUsageAnalyzeResponse getSpaceUsageAnalyze(SpaceUsageAnalyzeRequest spaceUsageAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceUsageAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);
        if(spaceUsageAnalyzeRequest.isQueryPublic()||spaceUsageAnalyzeRequest.isQueryAll()){
            //查询所有的图库或者公共图库
            //仅管理员才能访问
            boolean isAdmin = userService.isAdmin(loginUser);
            ThrowUtils.throwIf(!isAdmin,ErrorCode.NO_AUTH_ERROR);

            //统计公共图库的资源
            QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
            queryWrapper.select("picSize");
            if(!spaceUsageAnalyzeRequest.isQueryAll()){
                queryWrapper.isNull("spaceId");
            }
            List<Object> picObjList = pictureService.getBaseMapper().selectObjs(queryWrapper);
            long userSize = picObjList.stream().mapToLong(result->result instanceof Long?(Long)result:0).sum();
            long userCount = picObjList.size();
            //封装返回结果
            SpaceUsageAnalyzeResponse spaceUsageAnalyzeResponse = new SpaceUsageAnalyzeResponse();
            spaceUsageAnalyzeResponse.setUsedSize(userSize);
            spaceUsageAnalyzeResponse.setUsedCount(userCount);
            spaceUsageAnalyzeResponse.setMaxCount(null);
            spaceUsageAnalyzeResponse.setMaxSize(null);
            spaceUsageAnalyzeResponse.setCountUsageRatio(null);
            spaceUsageAnalyzeResponse.setSizeUsageRatio(null);
            return spaceUsageAnalyzeResponse;
        }else{
            //查询指定空间
            Long spaceId = spaceUsageAnalyzeRequest.getSpaceId();
            ThrowUtils.throwIf(spaceId==null,ErrorCode.PARAMS_ERROR);
            Space space = spaceService.getById(spaceId);
            ThrowUtils.throwIf(space == null, ErrorCode.NOT_FOUND_ERROR, "空间不存在");
            spaceService.checkSpaceAuth(loginUser,space);
            //构造返回结果
            SpaceUsageAnalyzeResponse response = new SpaceUsageAnalyzeResponse();
            response.setUsedSize(space.getTotalSize());
            response.setMaxSize(space.getMaxSize());
            //后端算好百分比
            double sizeUsageRatio = space.getTotalSize() * 100.0 / space.getMaxSize();
            response.setSizeUsageRatio(sizeUsageRatio);
            response.setUsedCount(space.getTotalCount());
            response.setMaxCount(space.getMaxCount());
            double countUsageRatio = space.getTotalCount() * 100.0 / space.getMaxCount();
            response.setCountUsageRatio(countUsageRatio);
            return response;
        }
    }

    @Override
    public List<SpaceCategoryAnalyzeResponse> getSpaceCategoryAnalyze(SpaceCategoryAnalyzeRequest spaceCategoryAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceCategoryAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);
        //检查权限
        checkSpaceAnalyzeAuth(spaceCategoryAnalyzeRequest,loginUser);

        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
        fillAnalyzeQueryWrapper(spaceCategoryAnalyzeRequest,queryWrapper);

        //使用mybatis-plus 分组查询
        queryWrapper.select("category AS category","COUNT(id) AS count","SUM(picSize) AS size")
                .groupBy("category");
        //更安全的转换机制，对返回的结果不是long类型或空的处理
        List<SpaceCategoryAnalyzeResponse> result = pictureService.getBaseMapper().selectMaps(queryWrapper).stream()
                .map(resultMap -> {
                    String category = resultMap.get("category")!=null?resultMap.get("category").toString():"未分类";
                    Long count = ((Number) resultMap.get("count")).longValue();
                    Long size = ((Number) resultMap.get("size")).longValue();
                    return new SpaceCategoryAnalyzeResponse(category, count, size);
                }).collect(Collectors.toList());
        return result;
    }
    @Override
    public List<SpaceTagAnalyzeResponse> getSpaceTagAnalyze(SpaceTagAnalyzeRequest spaceTagAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceTagAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);
        // 检查权限
        checkSpaceAnalyzeAuth(spaceTagAnalyzeRequest, loginUser);

        // 构造查询条件
        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
        fillAnalyzeQueryWrapper(spaceTagAnalyzeRequest, queryWrapper);

        // 查询所有符合条件的标签
        queryWrapper.select("tags");
        List<String> tagsJsonList = pictureService.getBaseMapper().selectObjs(queryWrapper)
                .stream()
                .filter(ObjUtil::isNotNull)
                .map(Object::toString)
                .collect(Collectors.toList());

        // 合并所有标签并统计使用次数
        Map<String, Long> tagCountMap = tagsJsonList.stream()
                .flatMap(tagsJson -> JSONUtil.toList(tagsJson, String.class).stream())
                .collect(Collectors.groupingBy(tag -> tag, Collectors.counting()));

        // 转换为响应对象，按使用次数降序排序
        return tagCountMap.entrySet().stream()
                .sorted((e1, e2) -> Long.compare(e2.getValue(), e1.getValue())) // 降序排列
                .map(entry -> new SpaceTagAnalyzeResponse(entry.getKey(), entry.getValue()))
                .collect(Collectors.toList());
    }

    @Override
    public List<SpaceSizeAnalyzeResponse> getSpaceSizeAnalyze(SpaceSizeAnalyzeRequest spaceSizeAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceSizeAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);

        // 检查权限
        checkSpaceAnalyzeAuth(spaceSizeAnalyzeRequest, loginUser);

        // 构造查询条件
        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
        fillAnalyzeQueryWrapper(spaceSizeAnalyzeRequest, queryWrapper);

        // 查询所有符合条件的图片大小
        queryWrapper.select("picSize");
        //TODO 为什么不用mapToLong
        List<Long> picSizes = pictureService.getBaseMapper().selectObjs(queryWrapper)
                .stream()
                .map(size -> ((Number) size).longValue())
                .collect(Collectors.toList());
        // 定义分段范围，注意使用有序 Map
        Map<String, Long> sizeRanges = new LinkedHashMap<>();
        sizeRanges.put("<100KB", picSizes.stream().filter(size -> size < 100 * 1024).count());
        sizeRanges.put("100KB-500KB", picSizes.stream().filter(size -> size >= 100 * 1024 && size < 500 * 1024).count());
        sizeRanges.put("500KB-1MB", picSizes.stream().filter(size -> size >= 500 * 1024 && size < 1 * 1024 * 1024).count());
        sizeRanges.put(">1MB", picSizes.stream().filter(size -> size >= 1 * 1024 * 1024).count());

        // 转换为响应对象
        return sizeRanges.entrySet().stream()
                .map(entry -> new SpaceSizeAnalyzeResponse(entry.getKey(), entry.getValue()))
                .collect(Collectors.toList());
    }
    @Override
    public List<SpaceUserAnalyzeResponse> getSpaceUserAnalyze(SpaceUserAnalyzeRequest spaceUserAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceUserAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);
        // 检查权限
        checkSpaceAnalyzeAuth(spaceUserAnalyzeRequest, loginUser);

        // 构造查询条件
        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
        Long userId = spaceUserAnalyzeRequest.getUserId();
        queryWrapper.eq(ObjUtil.isNotNull(userId), "userId", userId);
        fillAnalyzeQueryWrapper(spaceUserAnalyzeRequest, queryWrapper);

        // 分析维度：每日、每周、每月
        String timeDimension = spaceUserAnalyzeRequest.getTimeDimension();
        switch (timeDimension) {
            case "day":
                queryWrapper.select("DATE_FORMAT(createTime, '%Y-%m-%d') AS period", "COUNT(*) AS count");
                break;
            case "week":
                queryWrapper.select("YEARWEEK(createTime) AS period", "COUNT(*) AS count");
                break;
            case "month":
                queryWrapper.select("DATE_FORMAT(createTime, '%Y-%m') AS period", "COUNT(*) AS count");
                break;
            default:
                throw new BusinessException(ErrorCode.PARAMS_ERROR, "不支持的时间维度");
        }

        // 分组和排序
        queryWrapper.groupBy("period").orderByAsc("period");

        // 查询结果并转换
        List<Map<String, Object>> queryResult = pictureService.getBaseMapper().selectMaps(queryWrapper);
        return queryResult.stream()
                .map(result -> {
                    String period = result.get("period").toString();
                    Long count = ((Number) result.get("count")).longValue();
                    return new SpaceUserAnalyzeResponse(period, count);
                })
                .collect(Collectors.toList());
    }



    private static void fillAnalyzeQueryWrapper(SpaceAnalyzeRequest spaceAnalyzeRequest, QueryWrapper<Picture> queryWrapper) {
        if (spaceAnalyzeRequest.isQueryAll()) {
            return;
        }
        if (spaceAnalyzeRequest.isQueryPublic()) {
            queryWrapper.isNull("spaceId");
            return;
        }
        Long spaceId = spaceAnalyzeRequest.getSpaceId();
        if (spaceId != null) {
            queryWrapper.eq("spaceId", spaceId);
            return;
        }
        throw new BusinessException(ErrorCode.PARAMS_ERROR, "未指定查询范围");
    }

    @Override
    public List<Space> getSpaceRankAnalyze(SpaceRankAnalyzeRequest spaceRankAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceRankAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);
        ThrowUtils.throwIf(loginUser == null, ErrorCode.NOT_LOGIN_ERROR);
        //只有管理员才可以查看排行
        if (!userService.isAdmin(loginUser)) {
            ThrowUtils.throwIf(!userService.isAdmin(loginUser), ErrorCode.NO_AUTH_ERROR, "无权限查看排行");
        }
        QueryWrapper<Space> queryWrapper = new QueryWrapper<>();
        queryWrapper.select("id","spaceName","userId","totalSize")
                .orderByDesc("totalSize")
                .last("LIMIT " + spaceRankAnalyzeRequest.getTopN());//取前N名
        return spaceService.list(queryWrapper);
    }
}
